NASA Advisor: Mars Deserts Similar To Nevada's

Research on Mars is helping scientists better understand the life cycles of deserts on Earth and the potential to tap aquifers deep beneath the ground, an expert said Wednesday.

"All the pictures of the Martian surface are very similar if not identical to what we see in the very dry deserts of the Earth," said Farouk El-Baz, a longtime NASA adviser being honored this week by Nevada's Desert Research Institute.

"In both places we see these channels that were formed by rain in the geologic past. We see a mixture of rocks on the surface, very much like you see here today," he said in an interview.

"The deserts of Egypt are the driest and the heart of the Sahara would be very much like Mars," he said.

El-Baz, director of Boston University's Center for Remote Sensing, recently was awarded the silver 2004 Nevada Medal and $20,000 from DRI, the nonprofit environmental research affiliated with the state's university and college system. He gave lectures Tuesday and Wednesday in Reno and planned one Thursday at DRI's Las Vegas campus.

DRI President Stephen Wells said El-Baz pioneered the use of satellite images to characterize arid landforms worldwide.

"His research defined the role of alternating wet and dry climate cycles in desert regions and identified the forces that control the accumulation of groundwater in these regions," he said.

El-Baz' most recent research has focused on alternating dry and wet cycles on earth he said are common to all deserts.

"The deserts we see today were not as dry in the past as they are today," El-Baz told The Associated Press.

"We are now in a dry cycle. The vast deserts of the world have been through at least five changes, five phases, in the last half million years," he said.

The most recent wet cycle lasted from about 11,000 years ago to about 5,000 years ago, he said. It was preceded by a dry cycle, which was preceded by another wet cycle, from about 55,000 years ago to 25,000 years ago, he said.

El-Baz believes the cycles are largely the result of solar activity - the ebb and flow in the amount of energy the Earth receives from the sun based primarily on changes in the number of nuclear explosions on the sun's surface as well as the rotation of the sun on its own axis.

"When the earth receives a great deal of solar energy, the heating causes evaporation of water from the equatorial seas, which expands the cloud belt, which results in a great deal of rain and causes the desert to shrink," he said.

"During the years when the Earth receives less energy from the sun ... the desert expands," he said.

Within those major cycles are smaller cycles that also have an impact on deserts, he said.

Records of Nile River levels that the ancient Egyptians started 2,000 to 2,500 years ago suggest wet and dry cycles lasting about 135 years at a time.

"They kept very good records because that was the basis for the way they taxed farmers. The taxes were higher when the river was high," he said.

In addition, there is evidence of sun spots spiking in 22-year cycles, he said. There also appears to be some verification of the Holy Bible's references to 7-year drought cycles in Northern Africa and the Middle East - seven years of plenty followed by seven years of dryness and famine, he said.

"We are tying this all together," El-Baz said.

"It tells us there will be major climate changes over time caused by the sun, so we better find ways to monitor those changes so we can respond to them," he said.

A native of Egypt, El-Baz served as a science adviser to the late president of Egypt, Anwar Sadat. He currently is analyzing satellite images to evaluate ground water potential in arid tracts of eastern Arabia.

Because it rains a great deal during desert wet cycles, low areas like the U.S. Great Basin collected significant amounts of water at various times, he said.

"A great deal of that water would have seeped through the rock beneath. And much of it is still stored there as groundwater. That is why we should be looking for additional amounts of groundwater beneath deserts," he said.

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